Bimaterial thermally insulated container

ABSTRACT

The claimed invention relates to bi-material dual wall thermally insulated container. The outer wall of the dual wall insulated container is comprised of plastic and can be a decorated plastic product. The inner container is comprised of stainless steel. The inner container is fixed to the outer container creating a gap between the inner and the outer containers.

FIELD OF THE INVENTION

The present invention generally relates to thermally insulated containers. More specifically, the present invention relates to double-walled thermally insulated containers.

BACKGROUND OF THE INVENTION

Thermally insulated cups and containers are well known. Methods for the production and use of thermally insulated containers, such as coffee cups, are also well known. Thermally insulated cups are widely used for both hot and cold beverages. They are designed to maintain the beverage temperature by preventing undesirable heat transfer via the beverage inside the cup to/from the atmosphere or cup holder's hand. Currently available thermally insulated cups are generally made from aluminum, stainless steel, polymeric materials and combinations thereof.

Polymeric materials, such as polypropylene, polyethylene terephthalate (PET) based polyesters and polystyrenes are widely used as container materials for thermally insulated cups because of they are known to be relatively rigid and can be dishwasher safe. In some cases, such materials also provide for promotional and branding opportunities such as via in-mold labeling and even lenticular labeling.

Numerous methods of producing insulated plastic bottles and cups are disclosed in the prior art. However, containers made from such plastic materials often do not provide the appropriate beverage consuming experience, that is, the containers often retain flavors even when they have been thoroughly washed. Such retained flavors are likely to influence the flavor of newly poured beverages, which is highly undesirable.

Stainless steel vacuum insulated and stainless steel double wall coffee mugs are much better at resisting flavor retention. Additionally, such stainless steel vacuum insulated and double wall coffee mugs are generally considered to have a very attractive appearance. Stainless steel mugs may also have an advantage in their insulating qualities. With respect to the subject of safety, stainless steel is BPA free in addition to being free of other chemicals and toxins. Further, stainless steel is also rust, corrosion and stain resistant. Moreover, high quality stainless steel also tends to be resistant to bacteria and mold formation and is very resistant to retaining flavors after rinsing and/or washing. Unfortunately stainless steel mugs are often quite expensive, dent relatively easily, and are expensive and difficult to decorate permanently.

Accordingly, there is a need for an insulated container that provides excellent thermal insulation and barrier properties and provides a superior beverage consuming experience, that is, there is a need for insulated container that does not retain flavors. It would also be desirable to provide a product that can be conventionally decorated so that branding and promotional opportunities are possible. It would also be desirable to provide a product that is less expensive that stainless steel products and that is dent resistant.

SUMMARY OF THE INVENTION

The present invention relates to a thermally insulated double-walled container useful for containing hot or cold products and liquids. Thermally insulated double-walled disposable containers in accordance with the invention provide enhanced container structural integrity, better opportunities for decoration, improved insulation and a better beverage consuming experience.

In one aspect of the invention, a thermally insulated double-walled container includes a container body having an inner cup and an outer cup fixedly separated by a space. The thermally insulated double-walled container is open at the top and enclosed at the bottom. The space includes a gas for providing thermal insulation. A preferred gas is air. Insulating materials may be added to the space to enhance the thermal capabilities of the container. Preferred methods for making the plastic outer cup used in the insulated double-walled container include blow-molding, thermoforming or injecting molding. A preferred method for making the inner cup is forming the cup by pressing a sheet of stainless steel into a cup shape. The double-walled container is then created by fixedly connecting the inner cup to the outer cup to define an insulation space there between.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a container constructed in accordance with the claimed invention.

FIG. 2 is a cross-sectional view of one embodiment of a container constructed in accordance with the claimed invention.

FIG. 3 is a cross-sectional view of a second embodiment of a container constructed in accordance with the claimed invention.

DETAILED DESCRIPTION OF THE INVENTION

Now referring to the drawings in detail wherein like reference numerals refer to like elements throughout, FIG. 1 is a side perspective view of a container 101 manufactured in accordance with the claimed invention. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific container and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

The claimed invention relates to a two material dual wall insulated cup 101 and method for making the same, the two material container 101 assembly having insulating ability by having at least a “dual” structure wherein an inner container 121, in one embodiment, has a larger taper than an outer container 111 to form an insulating air layer or gap 135 between the inner container 111 and outer container 121. The present invention results in numerous advantages for the insulated container 101. Of primary importance to consumers of is that the dual wall insulated container 101: (1) does not retain flavors between washing; (2) is at least top rack dishwasher safe; (3) is thermally insulating for comfortable handling and for maintaining the temperature of its contents; (4) is sturdy enough to withstand prolonged handling, and (5) can be decorated, preferably using conventional methods such as in-mold labeling.

FIG. 2 shows a cross-section of a one embodiment of the present invention. Specifically, there is a cup assembly 101 comprised of an outer container 111 and an inner container 121. Outer container 111 has a frustoconical shape with side wall 113. The smaller end of outer cup 111 is closed and sealed by bottom wall 115. The larger end of outer cup 111 is open at 117. Typically, outer cup 111 is molded to create a lip 119 or ring around the open end 117. Typically, outer cup 111 comprises a molded material and more preferably an injected molded material. Outer cup 111 is typically decorated via in-mold labeling, although other methods of decoration are possible.

Inner cup 121 is also a frustoconically shaped with side wall 123. Inner cup 121 is slightly shorter in height than outer cup 111. The smaller end of inner cup 121 is closed and sealed by bottom wall 125. The larger end of inner cup 121 is open 127. Typically, the inner cup 121 of the claimed invention comprises stainless steel. The periphery of the open end 127 is typically uniformly bent or curled 129 over the lip at the open end 117 of the outer cup 111 and secured to the outer cup 111. As shown in FIG. 3, a gasket 141 can be used between the lip 119 of the outer cup 111 where the inner cup 111 is curled 129 over the lip 119 of the outer cup 111. Inner cup 121 may also contain surface protuberances 133. For example, inner cup 121 may have surface protuberances 133 in a threaded pattern as shown in FIG. 3 such that invention could further comprise a cover 151 further comprising a lower portion 153 comprising threads 155 complimentary to the threaded inner cup 121. In another embodiment, surface protuberances 133 could also be used to create a pressure seal with cover 151.

In one example, the cone angle of outer cup 111 is equal to or less than that of inner cup 121. As a result, an air space or gap 135 is created between side walls 113 and 123. An air gap 135 is also created between the bottom walls 115 of the inner cup 121 and the bottom wall 125 of the outer cup 111 in that inner cup 121 is shorter than the outer cup 111. Contacts 137 such as those illustrated between the inner cup 121 and the outer cup 111 may provide additional support surfaces so as to maintain the rigidity of the cup 101.

Other shapes for both the outer cup 111 and the inner cup 121 may also be advantageous. For example, coffee mugs are typically made in what is known as a “traveler” style. Traveler style coffee mugs have a base that fits within a standard-size cupholder. Additionally, inner cup 121 may be flared outwardly at the open end 127 such that a section of the side wall 123 of inner cup 121 is in contact with the side wall 113 of the outer cup 111. Such direct contact can enhance the structural rigidity of the cup 101 and therefore make for a more substantial feeling cup 101. An adhesive could also be used to secure the inner cup 121 to the outer cup 111. In particular, an adhesive could be used to secure the curled area 129 of the inner cup 121 over the lip 119 of the outer cup 111.

The size of the gap 135 between the inner cup 121 and the outer cup 111 as well as type of material and the thickness of the inner and/or outer cups have an effect on the insulating ability of the container. With respect to material type, it is understood that a polymer with a lower thermal coefficient will result in a greater heat transmission rates. Likewise, the thinner the material, the less time it will take before heat loss begins. In some cases, insulators such as batting situated between the inner cup 121 and the outer cup 111 may be used to improve the insulating capacity of the cup 101.

Examples of suitable plastics that may be used to form the outer cup 111 of the claimed container assembly 101 include, but are not limited to, thermoplastics such as polypropylene and polyethylene, but other plastics such as polystyrene may also be used. In a preferred embodiment, inner cup 121 is food grade stainless steel.

The container assembly 101 of the claimed invention can be produced in several different ways. Generally speaking, the outer cup 11I is injection molded. Conventional injection plastic molding techniques may be used for the outer cup 111. Optionally, outer cup 111 may further comprise an in-mold label or lenticular label. Inner cup 121 is formed of stainless steel it can be in the range of 0.009-0.05 inch and can be formed using any suitable forming technique.

Container assembly 101 is assembled by affixing inner cup 121 to outer cup 111 such that a gap remains between inner cup side wall 123 and outer cup side wall 113. In one embodiment, inner 121 cup is placed inside outer cup 111 such that the open end 127 of stainless steel inner cup 121 protrudes slightly from the open end 117 of the plastic outer cup 111. Excess portion of stainless steel inner cup 121 is then curled over the top of outer cup 111 or over lip 119 of outer cup 111 to form a curl 129 over the lip 119.

Preferably, a spinning operation is used to uniformly curl the excess portion of stainless steel inner cup 121 over the lip 119 of the outer cup 111. For example, once the inner cup 121 has been placed in the outer cup 121, the assembly can be mounted over a metal spinning mandrel. A roller tool is then placed against the excess portion of the stainless steel inner cup 121 gradually bending the excess portion of the stainless inner cup 121 around the lip 119 of the outer cup 111 to form the curl 131.

In a further preferred embodiment a gasket 131 is placed under and around the lip 119 of the outer cup 111. Thus, when the stainless inner cup 121 is bent around the lip of the outer cup 111 to form the curl 131, the gasket operates to seal the space between the inner cup 121 and the outer cup 111.

Preferred embodiments of this invention are described herein. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

What is claimed is:
 1. A dual wall cup assembly having an open end comprising: a plastic frustoconical shaped outer cup comprising an outer cup side wall, an upper open end further comprising a lip extending circumferentially outwardly from the upper open end and a closed smaller end sealed by a bottom wall; a stainless steel frustoconical shaped inner cup comprising an inner cup side wall, an upper open end and a closed smaller end sealed by a bottom wall; the size of the inner cup and the angle of the inner cup wall are configured to be receivable within the outer cup to create a gap between an inner surface of the side wall of the outer cup and an outer surface of the side wall of the inner cup and the inner cup side wall is slightly taller than the height of the outer cup side when the inner cup is received within the outer cup; and the slightly taller inner cup is curled over the lip of the upper open end of outer cup such that the outer cup and the inner cup are secured together by the curl of the inner cup over the outer cup.
 2. The dual wall cup assembly of claim 1 wherein the plastic frustoconical shaped outer cup is comprised of injection molded polypropylene.
 3. The dual wall cup assembly of claim 1 wherein the gap between the inner surface of the side wall of the outer cup and an outer surface of the side wall of the inner cup is relatively uniform.
 4. The dual wall cup assembly of claim 1 further comprising a gasket situated below the lip of the upper open end of the outer cup operable to seal the gap between the inner cup and the outer cup when the inner cup is bent over the lid of the upper open end of the outer cup.
 5. The dual wall cup assembly of claim 1 further comprising an adhesive sued to secure the outer cup to the inner cup.
 6. The dual wall cup assembly of claim 1 further comprising a cover.
 7. The dual wall cup assembly of claim 6 wherein the upper portion of the interior cup is threaded and the cover further comprises complimentary threads such that the cover is threadably securable to the cup.
 8. The dual wall assembly of claim 1 further comprising insulating batting situated the inner cup and the outer cup.
 9. The dual wall assembly of claim 1 